For me, the latest versions of Clp, Cbc and SCIP don’t seem to want to co-exist.
I think the CEnum entries in the [compat] section of the Project.toml files are incompatible:
Clp:  CEnum = "0.3"
Cbc:  CEnum = "0.3, 0.4"
SCIP: CEnum = "^0.1.0"
Can anyone else reproduce this, or is it just my setup?